Chemical mechanical polishing pad and methods of making and using same

ABSTRACT

Shape memory chemical mechanical polishing pads are provided, wherein the shape memory chemical mechanical polishing pads comprise a polishing layer in a densified state. Also provided are methods of making the shape memory chemical mechanical polishing pads and for using them to polish substrates.

The present invention relates generally to the field of polishing padsfor chemical mechanical polishing. In particular, the present inventionis directed to a shape memory chemical mechanical polishing pad having apolishing layer in a densified state useful for chemical mechanicalpolishing of magnetic, optical and semiconductor substrates.

In the fabrication of integrated circuits and other electronic devices,multiple layers of conducting, semiconducting and dielectric materialsare deposited onto and removed from a surface of a semiconductor wafer.Thin layers of conducting, semiconducting and dielectric materials maybe deposited using a number of deposition techniques. Common depositiontechniques in modern wafer processing include physical vapor deposition(PVD), also known as sputtering, chemical vapor deposition (CVD),plasma-enhanced chemical vapor deposition (PECVD) and electrochemicalplating, among others. Common removal techniques include wet and dryisotropic and anisotropic etching, among others.

As layers of materials are sequentially deposited and removed, theuppermost surface of the wafer becomes non-planar. Because subsequentsemiconductor processing (e.g., metallization) requires the wafer tohave a flat surface, the wafer needs to be planarized. Planarization isuseful for removing undesired surface topography and surface defects,such as rough surfaces, agglomerated materials, crystal lattice damage,scratches and contaminated layers or materials.

Chemical mechanical planarization, or chemical mechanical polishing(CMP), is a common technique used to planarize or polish workpieces suchas semiconductor wafers. In conventional CMP, a wafer carrier, orpolishing head, is mounted on a carrier assembly. The polishing headholds the wafer and positions the wafer in contact with a polishinglayer of a polishing pad that is mounted on a table or platen within aCMP apparatus. The carrier assembly provides a controllable pressurebetween the wafer and polishing pad. Simultaneously, a polishing medium(e.g., slurry) is dispensed onto the polishing pad and is drawn into thegap between the wafer and polishing layer. To effect polishing, thepolishing pad and wafer typically rotate relative to one another. As thepolishing pad rotates beneath the wafer, the wafer sweeps out atypically annular polishing track, or polishing region, wherein thewafer's surface directly confronts the polishing layer. The wafersurface is polished and made planar by chemical and mechanical action ofthe polishing layer and polishing medium on the surface.

For conventional polishing pads, pad surface “conditioning” or“dressing” is critical to maintaining a consistent polishing surface forstable polishing performance. Over time the polishing surface of thepolishing pad wears down, smoothing over the microtexture of thepolishing surface—a phenomenon called “glazing”. The origin of glazingis plastic flow of the polymeric material due to frictional heating andshear at the points of contact between the pad and the workpiece.Additionally, debris from the CMP process can clog the surface voids aswell as the micro-channels through which polishing medium flows acrossthe polishing surface. When this occurs, the polishing rate of the CMPprocess decreases and this can result in non-uniform polishing betweenwafers or within a wafer. Conditioning creates a new texture on thepolishing surface useful for maintaining the desired polishing rate anduniformity in the CMP process.

Conventional polishing pad conditioning is typically achieved byabrading the polishing surface mechanically with a conditioning disk.The conditioning disk has a rough conditioning surface typicallycomprised of imbedded diamond points. The conditioning disk is broughtinto contact with the polishing surface either during intermittentbreaks in the CMP process when polishing is paused (“ex situ”), or whilethe CMP process is underway (“in situ”). Typically the conditioning diskis rotated in a position that is fixed with respect to the axis ofrotation of the polishing pad, and sweeps out an annular conditioningregion as the polishing pad is rotated. The conditioning process asdescribed cuts microscopic furrows into the pad surface, both abradingand plowing the pad material and renewing the polishing texture.

The diamonds on conventional conditioning disks become dulled with usesuch that the conditioning disk must be replaced after a period of time.Also, during their useful life the effectiveness of conditioning diskscontinually changes.

Conventional conditioning processes contribute greatly to the wear rateof CMP pads. It is common for about 95% of the wear of a pad to resultfrom the abrasion of the diamond conditioner and only about 5% fromactual contact with workpieces (e.g., semiconductor wafers).

One approach to improving CMP process efficiency is disclosed in U.S.Pat. No. 5,736,463 to Sato. Sato discloses a method for chemicalmechanical polishing comprising the use of a polishing pad containingstructures made of a shape memory material, wherein the structures havean upright state relative to said polishing pad before being used forpolishing and a fatigue state after being used for polishing, whereinupon cessation of polishing, said structures made of a shape memorymaterial return to said upright state.

Notwithstanding, there is a continuing need for CMP polishing padshaving a polishing surface that can be renewed with a minimum ofabrasive conditioning, hence extending the useful pad life.

In one aspect of the present invention, there is provided a shape memorychemical mechanical polishing pad for polishing a substrate selectedfrom at least one of a magnetic substrate, an optical substrate and asemiconductor substrate; comprising: a polishing layer in a densifiedstate; wherein the polishing layer comprises a shape memory matrixmaterial transformable between an original shape and a programmed shape;wherein the polishing layer exhibits an original thickness, OT, when theshape memory matrix material is in the original shape; wherein thepolishing layer exhibits a densified thickness, DT, in the densifiedstate when the shape memory matrix material is in the programmed shape;wherein the DT is <80% of the OT; wherein the shape memory matrixmaterial exhibits a ≧70% reduction in storage modulus as the temperatureof the shape memory matrix material is raised from (T_(g)−20)° C. to(T_(g)+20)° C.; and, wherein the polishing layer has a polishing surfaceadapted for polishing the substrate.

In another aspect of the present invention, there is provided a methodfor producing a shape memory chemical mechanical polishing pad,comprising: providing a shape memory matrix material transformablebetween an original shape and a programmed shape; preparing a polishinglayer in an original state exhibiting an original thickness, OT,comprising the shape memory matrix material in the original shape;subjecting the polishing layer to an external force; setting the shapememory matrix material to the programmed shape to provide the polishinglayer in a densified state, wherein the polishing layer exhibits adensified thickness, DT; removing the external force; wherein the DT is≦80% of the OT; wherein the shape memory matrix material exhibits a ≧70%reduction in storage modulus as the temperature of the shape memorymatrix material is raised from (T_(g)−20)° C. to (T_(g)+20)° C.; and,wherein the polishing layer has a polishing surface adapted forpolishing a substrate selected from at least one of a magneticsubstrate, an optical substrate and a semiconductor substrate.

In another aspect of the present invention, there is provided a methodof polishing a substrate, comprising: providing a substrate selectedfrom at least one of a magnetic substrate, an optical substrate and asemiconductor substrate; providing a shape memory chemical mechanicalpolishing pad, wherein the polishing pad comprises a polishing layer ina densified state, wherein the polishing layer comprises a shape memorymatrix material transformable from an original shape and a programmedshape; wherein the polishing layer in the original state exhibits anoriginal thickness, OT, when the shape memory matrix material is in theoriginal shape; wherein the polishing layer exhibits a densifiedthickness, DT, in the densified state when the shape memory matrixmaterial is in the programmed shape; and wherein the DT is ≦80% of theOT; wherein the shape memory matrix material exhibits a ≧70% reductionin storage modulus as the temperature of the shape memory matrixmaterial is raised from (T_(g)−20)° C. to (T_(g)+20)° C.; and, creatingdynamic contact between a polishing surface of the polishing layer andthe substrate to polish a surface of the substrate.

In another aspect of the present invention, there is provided a methodof polishing a substrate, comprising: providing a substrate selectedfrom at least one of a magnetic substrate, an optical substrate and asemiconductor substrate; providing a shape memory chemical mechanicalpolishing pad, wherein the polishing pad comprises a polishing layer ina densified state, wherein the polishing layer comprises a shape memorymatrix material transformable from an original shape and a programmedshape; wherein the polishing layer in the original state exhibits anoriginal thickness, OT, when the shape memory matrix material is in theoriginal shape; wherein the polishing layer exhibits a densifiedthickness, DT, in the densified state when the shape memory matrixmaterial is in the programmed shape; and wherein the DT is ≦80% of theOT; wherein the shape memory matrix material exhibits a ≧70% reductionin storage modulus as the temperature of the shape memory matrixmaterial is raised from (T_(g)−20)° C. to (T_(g)+20)° C.; creatingdynamic contact between a polishing surface of the polishing layer andthe substrate to polish a surface of the substrate and conditioning thepolishing surface of the polishing layer by exposing at least a portionof the polishing layer proximate the polishing surface to an activatingstimulus, wherein the portion of the polishing layer proximate thepolishing surface exposed to the activating stimulus transitions fromthe densified state to a recovered state.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a comparative depiction of an elevation view of polishinglayer of the present invention in an original state and a densifiedstate.

FIG. 2 is a comparative depiction of an elevation view of a polishinglayer of the present invention in an original state, a densified stateand a partially recovered state.

FIG. 3 is an elevation view of a shape memory chemical mechanicalpolishing pad of one embodiment of the present invention.

FIG. 4 is a side perspective view of a shape memory chemical mechanicalpolishing pad of one embodiment of the present invention.

FIG. 5 is a top plan view of a shape memory chemical mechanicalpolishing pad of one embodiment of the present invention depicting agroove pattern in the polishing surface.

FIG. 6 is a top plan view of a shape memory chemical mechanicalpolishing pad of one embodiment of the present invention depicting agroove pattern in the polishing surface.

FIG. 7 is a top plan view of a shape memory chemical mechanicalpolishing pad of one embodiment of the present invention depicting agroove pattern in the polishing surface.

FIG. 8 is a top plan view of a shape memory chemical mechanicalpolishing pad of one embodiment of the present invention depicting acombination of perforations and groove pattern in the polishing surface.

FIG. 9 is a top plan view of a shape memory chemical mechanicalpolishing pad of one embodiment of the present invention depicting aplurality of perforations in the polishing surface.

FIG. 10 is a top plan view of a shape memory chemical mechanicalpolishing pad of one embodiment of the present invention with a groovepattern in the polishing surface.

FIG. 11 is a top plan view of a shape memory chemical mechanicalpolishing pad of one embodiment of the present invention with a groovepattern in the polishing surface, wherein the polishing pad exhibits a24 inch pad outer radius R_(O) and a 10 inch base radius R_(B); and 8curved grooves.

FIG. 12 is a top plan view of a shape memory chemical mechanicalpolishing pad of one embodiment of the present invention with a groovepattern in the polishing surface, wherein the polishing pad exhibits a24 inch pad outer radius R_(O); a 6 inch base radius R_(B); and 8 curvedgrooves.

FIG. 13 is a top plan view of a shape memory chemical mechanicalpolishing pad of one embodiment of the present invention with a groovepattern in the polishing surface, wherein the polishing pad exhibits a24 inch pad outer radius R_(O) and a 2 inch base radius R_(B).

FIG. 14 is a close-up view of a groove segment of groove 404 of FIG. 10.

FIG. 15 is a depiction of a polishing machine utilizing a shape memorychemical mechanical polishing pad of the present invention to polish asemiconductor wafer.

FIG. 16 is a depiction of a polishing apparatus utilizing a shape memorychemical mechanical polishing pad of the present invention incombination with a polishing slurry to polish a semiconductor wafer.

FIG. 17 is a graph providing a storage modulus versus temperature curvefor the composition used in commercial IC1000™ polishing pads.

FIG. 18 is a graph providing storage modulus versus temperature curvesfor two shape memory matrix materials.

FIG. 19 is a graphical representation of the removal rate versus thenumber of wafers polished using a commercial IC1000™ polishing pad in anoriginal state using diamond disk conditioning.

FIG. 20 is a graphical representation of the removal rate versus thenumber of wafers polished using an IC1000™ polishing pad in a densifiedstate using thermal conditioning.

FIG. 21 is a graph providing storage modulus versus temperature curvesfor another shape memory matrix material.

DETAILED DESCRIPTION

The term “fibrillar morphology” as used herein and in the appendedclaims refers to a morphology of a phase in which the phase domains havea three dimensional shape with one dimension much larger than the othertwo dimensions.

The term “polishing medium” as used herein and in the appended claimsencompasses particle-containing polishing solutions andnon-particle-containing solutions, such as abrasive-free andreactive-liquid polishing solutions.

The term “substantial relaxation” as used herein and in the appendedclaims means a sufficient relaxation in the shape memory matrix materialin the polishing layer to cause a ≧2% increase in the polishing layer'saverage thickness measured using a granite base comparator (e.g., aChicago Dial Indicator Cat#6066-10).

The term “substantially circular cross section” as used herein and inthe appended claims in reference to the polishing surface means that theradius, r, of the cross section from the central axis to the outerperiphery of the polishing surface varies by ≦20% for the cross section.(See FIG. 4).

The glass transition temperature (“Tg”) as used herein and in theappended claims is measured by the dynamical mechanical analysis (DMA)taking the inflection point in the storage modulus versus temperaturecurve as the T_(g) value.

The term “original state” as used herein and in the appended claims inreference to a polishing layer of a shape memory chemical mechanicalpolishing pad of the present invention means the as made state beforesubjecting it to an external force to “lock-in” a reversible shapedeformation to set the polishing layer in a densified state.

The term “microtexture” used herein and in the appended claims inreference to the polishing surface refers to the intrinsic microscopicbulk texture of the polishing surface after manufacture. Some of thefactors which influence the static morphology or microscopic bulktexture of the polishing surface are the nature and texture includingwaves, holes, creases, ridges, slits, depressions, protrusions and gaps,and the size, shape and distribution, frequency or spacing of individualfeatures or artifacts. The microtexture is typically largely random andis the result of factors intrinsic to the manufacturing process of thepolishing layer.

The term “macrotexture” as used herein and in the appended claims inreference to the polishing surface refers to larger size texturedartifacts that may be imposed by embossing, skiving, perforating and/ormachining of the polishing surface.

The term “circumference fraction grooved” or “CF” as used herein and inthe appended claims is defined by the following formula:

${CF} = \left\{ \frac{\begin{pmatrix}{{{Portion}\mspace{14mu}{of}\mspace{14mu}{circumference}\mspace{14mu}{at}\mspace{14mu} a\mspace{14mu}{given}\mspace{14mu}{radius}},R,} \\{{that}\mspace{14mu}{lies}\mspace{14mu}{across}\mspace{14mu}{any}\mspace{14mu}{groove}}\end{pmatrix}}{\left( {{{Full}\mspace{14mu}{circumference}\mspace{14mu}{at}\mspace{14mu}{the}\mspace{14mu}{given}\mspace{14mu}{radius}},R} \right)} \right\}$Note that if CF is constant as a function of radius for the polishingsurface of a given shape memory chemical mechanical polishing pad, thenthe fractional portion of the polishing surface that is grooved (orungrooved) at a given radius will also be constant as a function ofradius.

The term “shape memory matrix material” as used herein and in theappended claims refers to materials that have the ability to exhibit ashape memory effect. That is, any materials or combination of materialsthat exhibit the following properties: (1) are capable of being deformedin at least one spatial dimension when exposed to an external force, (2)are capable of locking-in and maintaining a degree of the deformation inat least one spatial dimension after removal of the external force, and(3) are capable of exhibiting a recovery in at least one spatialdimension when subjected to an activating stimulus. Shape memory matrixmaterials are a class of smart materials that are designed andmanufactured to react in a predetermined way according to changes intheir environment. Shape memory matrix materials can be deformed from anoriginal shape and fixed into a temporary (programmed) shape and uponexposure to an activating stimulus react to recover to a recovered shapethat approximates the original shape.

The shape memory effect involves the programming of a “programmed shape”in a shape memory matrix material and subsequently causing the shapememory matrix material to recover to a “recovered shape” (whichapproximates the original shape) upon exposure of the shape memorymatrix material to an activating stimulus. A shape memory matrixmaterial is processed into the original shape by conventional methods.Subsequently it is deformed by exposure to an external force and adesired programmed shape is fixed. This later process is referred toherein as programming.

The “storage modulus” for a shape memory matrix material of the presentinvention is a measure of the stored elastic energy in the shape memorymatrix material. The storage modulus represents a ratio of the stress inphase (with the strain) to the applied strain and is measured using a TAQ800 Dynamic Mechanical Analyzer using a single-cantilever clamp setupand a “multi-frequency-strain” testing mode of the instrument.

In some embodiments of the present invention, the shape memory chemicalmechanical polishing pad for polishing a substrate selected from atleast one of a magnetic substrate, an optical substrate and asemiconductor substrate; comprising: a polishing layer in a densifiedstate; wherein the polishing layer comprises a shape memory matrixmaterial transformable between an original shape and a programmed shape;wherein the polishing layer exhibits an original thickness, OT, when theshape memory matrix material is in the original shape; wherein thepolishing layer exhibits a densified thickness, DT, in the densifiedstate when the shape memory matrix material is in the programmed shape;wherein the DT is ≦80% of the OT; wherein the shape memory matrixmaterial exhibits a ≧70% reduction in storage modulus as the temperatureof the shape memory matrix material is raised from (T_(g)−20)° C. to(T_(g)+20)° C.; and, wherein the polishing layer has a polishing surfaceadapted for polishing the substrate. In some aspects of theseembodiments, the shape memory matrix material exhibits a ≧75% reduction;≧80% reduction; ≧85% reduction; or ≧90% reduction in storage modulus asthe temperature of the shape memory matrix material is raised from(T_(g)−20)° C. to (T_(g)+20)° C.; (T_(g)−10)° C. to (T_(g)+10)° C.; or(T_(g)−5)° C. to (T_(g)+5)° C. In some aspects of these embodiments, thereduction in storage modulus has a magnitude of ≧800 MPa; ≧900 MPa;≧1,000 MPa; ≧800 MPa and ≦10,000 MPa; ≧800 MPa and ≦5,000 MPa; or ≧800MPa and ≦2,500 MPa. In some aspects of these embodiments, the shapememory matrix material exhibits a ≧90% reduction in storage modulus asthe temperature of the shape memory matrix material is raised from(T_(g)−10)° C. to (T_(g)+10)° C., wherein the reduction in storagemodulus has a magnitude of ≧800 MPa.

In some embodiments of the present invention, the shape memory matrixmaterial is selected to exhibit a transition in storage modulus over atemperature range. Generally speaking, the higher the magnitude of thetransition in storage modulus and the narrower the temperature rangeover which the transition occurs, the better the shape memory effect forthe shape memory matrix material.

In some embodiments of the present invention, the shape memory matrixmaterial comprises at least one polymer. In some aspects of theseembodiments, the shape memory matrix material comprises at least onepolymer selected from segmented block copolymers comprising at least onehard segment and at least one soft segment. In some aspects of theseembodiments, the shape memory matrix material comprises at least onepolymer selected from polyester based thermoplastic polyurethanes;polyether based polyurethanes; polyethylene oxide; poly(ether ester)block copolymers; polyamides; poly(amide esters); poly(ether amide)copolymers; polyvinyl alcohol; polyvinyl pyrrolidone; polyvinylpyridine; polyacrylic acid; polymethacrylic acid; polyaspartic acid;maleic anhydride methylvinyl ether copolymers; polyvinyl methyl ethercopolymers of polyacrylic acid and polyacrylic esters; styrenicpolymers; epoxide based polymers; polycyanurates; and combinationsthereof (e.g., copolymers and blends). In some aspects of theseembodiments, the shape memory matrix material comprises a segmentedblock copolymer comprising at least one hard segment and at least onesoft segment, where either the soft segment, the hard segment, or bothcontain functional groups or receptor sites that are “stimuliresponsive”, i.e. that enable a desired amount of shape recovery whenexposed to an activating stimulus.

In some embodiments of the present invention, the shape memory matrixmaterial comprises a segmented block copolymer. In some aspects of theseembodiments, the segmented block copolymer is selected from polyurethaneelastomers, polyether elastomers, poly(ether amide) elastomers,polyether polyester elastomers, polyamide-based elastomers,thermoplastic polyurethanes, poly(ether-amide) block copolymers,thermoplastic rubbers (e.g., uncrosslinked polyolefins),styrene-butadiene copolymers, silicon rubbers, synthetic rubbers (e.g.,nitrile rubber and butyl rubber), ethylene-vinyl acetate copolymers,styrene-isoprene copolymers, styrene-ethylene-butylene copolymers andcombinations thereof. In some aspects of these embodiments, the shapememory matrix material further comprises a non-elastomeric polymer. Insome aspects of these embodiments, the non-elastomeric polymer isselected from polyethylene oxide, copolymers of polylactic acid andcombinations thereof.

In some embodiments of the present invention, the shape memory matrixmaterial comprises a polyurethane. In some aspects of these embodiments,the polyurethane is selected from polyester-based aromaticpolyurethanes; polyester-based aliphatic polyurethanes; polyether-basedaliphatic and aromatic polyurethanes; and combinations thereof.

In some embodiments of the present invention, the shape memory matrixmaterial comprises a reaction product of a mixture comprising apolyether-based, toluene diisocyanate terminated liquid urethaneprepolymer; and a 4,4′-methylene-bis(2-chloroaniline).

In some embodiments of the present invention, the shape memory matrixmaterial comprises a reaction product of a mixture comprising glycerolpropoxylate; polycarbodiimide-modified diphenylmethane diisocyanate; andat least one of polytetrahydrofuran and polycaprolactone. In someaspects of these embodiments, the shape memory matrix material comprisesa reaction product of a mixture comprising glycerol propoxylate;polycarbodiimide-modified diphenylmethane diisocyanate; andpolytetrahydrofuran. In some aspects of these embodiments, the shapememory matrix material comprises a reaction product of a mixturecomprising glycerol propoxylate; polycarbodiimide-modifieddiphenylmethane diisocyanate; and polycaprolactone.

In some embodiments of the present invention, the shape memory matrixmaterial is selected to exhibit a T_(g) of ≧45° C. and ≦80° C. In someaspects of these embodiments, the shape memory matrix material isselected to exhibit a T_(g) of ≧45° C. and ≦75° C.; ≧50° C. and ≦75° C.;≧55° C. and ≦75° C.; ≧55° C. and ≦70° C.; or ≧55° C. and ≦65° C.

In some embodiments of the present invention, the polishing layerfurther comprises a plurality of microelements. In some aspects of theseembodiments, the plurality of microelements is uniformly dispersedwithin the polishing layer. In some aspects of these embodiments, theplurality of microelements are selected from entrapped gas bubbles,hollow core polymeric materials, liquid filled hollow core polymericmaterials, water soluble materials and an insoluble phase material(e.g., mineral oil). In some aspects of these embodiments, the pluralityof microelements comprises hollow core polymeric materials uniformlydistributed throughout the polishing layer.

In some embodiments of the present invention, the polishing layerfurther comprises a plurality of microelements, wherein the plurality ofmicroelements comprise gas filled hollow core polymer particles. In someaspects of these embodiments, at least a portion of the hollow corepolymer particles are generally flexible.

In some embodiments of the present invention, the polishing layerfurther comprises a plurality of microelements, wherein the plurality ofmicroelements comprises fluid filled hollow core polymer particles. Insome aspects of these embodiments, the microelements are filled with apolishing fluid that is dispensed when the microelements are ruptured byabrasion when the polishing pad is used during a polishing operation.

In some embodiments of the present invention, the polishing layerfurther comprises a plurality of microelements, wherein the plurality ofmicroelements comprise water soluble materials that are dissolved bywater present during a polishing operation. In some aspects of theseembodiments, the plurality of microelements are selected from watersoluble inorganic salts, water soluble sugars and water solubleparticles. In some aspects of these embodiments, the plurality ofmicroelements are selected from polyvinyl alcohols, pectin, polyvinylpyrrolidone, hydroxyethylcellulose, methylcellulose,hydropropylmethylcellulose, carboxymethylcellulose,hydroxypropylcellulose, polyacrylic acids, polyacrylamides, polyethyleneglycols, polyhydroxyetheracrylites, starches, maleic acid copolymers,polyethylene oxide, polyurethanes, cyclodextrin and combinationsthereof. In some aspects of these embodiments, the plurality ofmicroelement has a weight average particle size of 10 to 100 μm. In someaspects of these embodiments, the plurality of microelements have aweight average particle size of 15 to 90 μm. In some aspects of theseembodiments, the plurality of microelements have a weight averageparticle size of 15 to 50 μm. In some aspects of these embodiments, theplurality of microelements can be chemically modified to change thesolubility, swelling and other properties thereof by, for example,branching, blocking, and crosslinking. In some aspects of theseembodiments, the plurality of microelements comprises a hollow corecopolymer of polyacrylonitrile and polyvinylidene chloride (e.g.,Expancel™ from Akzo Nobel of Sundsvall, Sweden). In some aspects ofthese embodiments, the plurality of microelements comprises acyclodextrine.

In some embodiments of the present invention, the polishing layercomprises a shape memory matrix material that forms a lattice structure.In some aspects of these embodiments, the polishing layer comprises ≦70vol % shape memory matrix material when the polishing layer is in theoriginal state. In some aspects of these embodiments, the polishinglayer comprises at least two repeating layers of lattice structure.

In some embodiments of present invention, the shape memory matrixmaterial in the polishing layer forms a reticulated network. In someaspects of these embodiments, the reticulated network exhibits a gyroidmorphology. In some aspects of these embodiments, the reticulatednetwork exhibits a fibrillar morphology. In some aspects of theseembodiments, the reticulated network comprises an interconnected networkof structural members. In some aspects of these embodiments, theinterconnected network of structural members comprehends openinterconnected networks in which individual elements are positioned atall angles from fully horizontal to fully vertical. In some aspects ofthese embodiments, the interconnected network comprises entirely randomarrays of interconnected slender elements in which there is no clearlyrepeating size or shape to the void spaces formed thereby. In someaspects of these embodiments, the polishing layer comprises a shapememory matrix material formed into entirely random arrays ofinterconnected slender elements in which there is no clearly repeatingsize or shape to the void spaces, or where many elements are highlycurved, branched, or entangled. In some aspects of these embodiments,the interconnected network may resemble bridge trusses, stick models ofmacromolecules, and interconnected human nerve cells.

In some embodiments of the present invention, the polishing layer has acombined porosity and/or microelement concentration of 0.2 to 80 vol %when the polishing layer is in the original state. In some aspects ofthese embodiments, the polishing layer has a combined porosity and/ormicroelement concentration of 0.3 to 80 vol % when the polishing layeris in the original state. In some aspects of these embodiments, thepolishing layer has a combined porosity and/or microelementconcentration of 0.55 to 70 vol % when the polishing layer is in theoriginal state. In some aspects of these embodiments, the polishinglayer has a combined porosity and/or microelement concentration of 0.6to 60 vol % when the polishing layer is in the original state.

In some embodiments of the present invention the shape memory chemicalmechanical polishing pad for polishing a substrate selected from atleast one of a magnetic substrate, an optical substrate and asemiconductor substrate; comprises: a polishing layer in a densifiedstate; wherein the polishing layer comprises a shape memory matrixmaterial transformable between an original shape (i.e., an as madeshape) and a programmed shape; wherein the polishing layer exhibits anoriginal thickness, OT, when the shape memory matrix material is in theoriginal shape; wherein the polishing layer exhibits a densifiedthickness, DT, in the densified state when the shape memory matrixmaterial is in the programmed shape; wherein the DT is ≦80% of the OT;and, wherein the polishing layer has a polishing surface adapted forpolishing the substrate. In some aspects of these embodiments, thedensified thickness, DT, is ≦70% of the original thickness, OT. In someaspects of these embodiments, the densified thickness, DT, is between 70and 40% of the original thickness, OT. In some aspects of theseembodiments, the substrate is a semiconductor substrate. In some aspectsof these embodiments, the substrate is a semiconductor wafer.

In some embodiments of the present invention, the polishing layer has adensified thickness of 20 to 150 mils. In some aspects of theseembodiments, the polishing layer has a densified thickness of 30 to 125mils. In some aspects of these embodiments, the polishing layer has adensified thickness of 40 to 120 mils.

In some embodiments of the present invention, the shape memory chemicalmechanical polishing pad is adapted to be interfaced with a platen of apolishing machine. In some aspects of these embodiments, the shapememory chemical mechanical polishing pad is adapted to be affixed to theplaten. In some aspects of these embodiments, the shape memory chemicalmechanical polishing pad is adapted to be affixed to the platen using atleast one of a pressure sensitive adhesive and vacuum.

In some embodiments of the present invention, the shape memory chemicalmechanical polishing pad has a central axis and is adapted for rotationabout the central axis. (See FIG. 4). In some aspects of theseembodiments, the polishing layer 210 of the shape memory chemicalmechanical polishing pad is in a plane substantially perpendicular tothe central axis 212. In some aspects of these embodiments, thepolishing layer 210 is adapted for rotation in a plane that is at anangle, γ, of 80 to 100° to the central axis 212. In some aspects ofthese embodiments, the polishing layer 210 is adapted for rotation in aplane that is at an angle, γ, of 85 to 95° to the central axis 212. Insome aspects of these embodiments, the polishing layer 210 is adaptedfor rotation in a plane that is at an angle, γ, of 89 to 91° to thecentral axis 212. In some aspects of these embodiments, the polishinglayer 210 has a polishing surface 214 that has a substantially circularcross section perpendicular to the central axis 212. In some aspects ofthese embodiments, the radius, r, of the cross section of the polishingsurface 214 perpendicular to the central axis 212 varies by ≦20% for thecross section. In some aspects of these embodiments, the radius, r, ofthe cross section of the polishing surface 214 perpendicular to thecentral axis 212 varies by ≦10% for the cross section.

In some embodiments of the present invention, the shape memory chemicalmechanical polishing pad comprises a polishing layer interfaced with abase layer. In some aspects of these embodiments, the polishing layer isattached to the base layer using an adhesive. In some aspects of theseembodiments, the adhesive is selected from pressure sensitive adhesives,hot melt adhesives, contact adhesives and combinations thereof. In someaspects of these embodiments, the adhesive is a hot melt adhesive. Insome aspects of these embodiments, the adhesive is a contact adhesive.In some aspects of these embodiments, the adhesive is a pressuresensitive adhesive.

In some embodiments of the present invention, the shape memory chemicalmechanical polishing pad comprises a polishing layer, a base layer andat least one additional layer interposed between the base layer and thepolishing layer.

In some embodiments of the present invention, the shape memory chemicalmechanical polishing pad has a polishing surface exhibiting at least oneof macrotexture and microtexture to facilitate polishing the substrate.

In some embodiments of the present invention, the shape memory chemicalmechanical polishing pad has a polishing surface exhibitingmacrotexture. In some aspects of these embodiments, the macrotexture isdesigned to alleviate at least one of hydroplaning; to influencepolishing medium flow; to modify the stiffness of the polishing layer;to reduce edge effects; and, to facilitate the transfer of polishingdebris away from the area between the polishing surface and thesubstrate.

In some embodiments of the present invention, the shape memory chemicalmechanical polishing pad has a polishing surface exhibiting macrotextureselected from at least one of perforations and grooves. In some aspectsof these embodiments, the perforations can extend from the polishingsurface part way or all of the way through the actual thickness of thepolishing layer. In some aspects of these embodiments, the grooves arearranged on the polishing surface such that upon rotation of the padduring polishing, at least one groove sweeps over the substrate. In someaspects of these embodiments, the grooves are selected from curvedgrooves, linear grooves and combinations thereof.

In some embodiments of the present invention, the polishing layer has amacrotexture comprising a groove pattern. In some aspects of theseembodiments, the groove pattern comprises at least one groove. In someaspects of these embodiments, the groove pattern comprises a pluralityof grooves. In some aspects of these embodiments, the at least onegroove is selected from curved grooves, straight grooves andcombinations thereof. In some aspects of these embodiments, the groovepattern is selected from a groove design including, for example,concentric grooves (which may be circular or spiral), curved grooves,cross-hatch grooves (e.g., arranged as an X-Y grid across the padsurface), other regular designs (e.g., hexagons, triangles), tire-treadtype patterns, irregular designs (e.g., fractal patterns), andcombinations thereof. In some aspects of these embodiments, the groovepattern is selected from random, concentric, spiral, cross-hatched, X-Ygrid, hexagonal, triangular, fractal and combinations thereof. In someaspects of these embodiments, the groove profile is selected fromrectangular with straight side-walls or the groove cross-section may be“V”-shaped, “U”-shaped, triangular, saw-tooth, and combinations thereof.In some aspects of these embodiments, the groove pattern is a groovedesign that changes across the polishing surface. In some aspects ofthese embodiments, the groove design is engineered for a specificapplication. In some aspects of these embodiments, the groove dimensionsin a specific design may be varied across the pad surface to produceregions of different groove densities.

In some embodiments of the present invention, the shape memory chemicalmechanical polishing pad has a macrotexture comprising a groove patternthat comprises at least one groove, wherein CF remains within 25%,preferably within 10%, more preferably within 5% of its average value asa function of a polishing pad radius, R, in an area extending from anouter radius, R_(O), of a polishing surface a majority distance to anorigin, O, at a center of the polishing surface. In some aspects ofthese embodiments, CF remains within 25%, preferably within 10%, morepreferably within 5% of its average value as a function of a polishingpad radius, R, in an area extending from a base radius, R_(B), to anouter radius, R_(O). (See, e.g., FIG. 10).

In some embodiments of the present invention, the shape memory chemicalmechanical polishing pad has a macrotexture comprising at least onegroove. In some aspects of these embodiments, the at least one groovehas a depth of ≧20 mils. In some aspects of these embodiments, the atleast one groove has a depth of 20 to 100 mils. In some aspects of theseembodiments, the at least one groove has a depth of 20 to 60 mils. Insome aspects of these embodiments, the at least one groove has a depthof 20 to 50 mils.

In some embodiments of the present invention, the shape memory chemicalmechanical polishing pad has a macrotexture comprising a groove patternthat comprises at least two grooves having a depth of ≧15 mils; a widthof ≧10 mils and a pitch of ≧50 mils. In some aspects of theseembodiments, the groove pattern comprises at least two grooves having adepth of ≧20 mils; a width of ≧15 mils and a pitch of ≧70 mils. In someaspects of these embodiments, the groove pattern comprises at least twogrooves having a depth of ≧20 mils; a width of ≧15 mils and a pitch of≧90 mils.

In some embodiments of the present invention, the shape memory chemicalmechanical polishing pad has a polishing surface that exhibitsmicrotexture.

In some embodiments of the present invention, the method for producing ashape memory chemical mechanical polishing pad, comprises: providing ashape memory matrix material transformable between an original shape anda programmed shape; preparing a polishing layer in an original stateexhibiting an original thickness, OT, comprising the shape memory matrixmaterial in the original shape; subjecting the polishing layer to anexternal force; setting the shape memory matrix material to theprogrammed shape to provide the polishing layer in a densified state,wherein the polishing layer exhibits a densified thickness, DT; removingthe external force; wherein the DT is ≦80% of the OT; wherein the shapememory matrix material exhibits a ≧70% reduction in storage modulus asthe temperature of the shape memory matrix material is raised fromT_(g)−20° C. to T_(g)+20° C.; and, wherein the polishing layer has apolishing surface adapted for polishing a substrate selected from atleast one of a magnetic substrate, an optical substrate and asemiconductor substrate. In some aspects of these embodiments, thedensified thickness, DT, is ≦70% of the original thickness, OT. In someaspects of these embodiments, the densified thickness, DT, is between 70and 40% of the original thickness, OT. In some aspects of theseembodiments, the shape memory matrix material exhibits a ≧75% reduction;≧80% reduction; ≧85% reduction; or ≧90% reduction in storage modulus asthe temperature of the shape memory matrix material is raised from(T_(g)−20)° C. to (T_(g)+20)° C.; (T_(g)−10)° C. to (T_(g)+10)° C.; or(T_(g)−5)° C. to (T_(g)+5)° C. In some aspects of these embodiments, thereduction in storage modulus has a magniture of ≧800 MPa; ≧900 MPa;≧1,000 MPa; ≧800 MPa and ≦10,000 MPa; ≧800 MPa and ≦5,000 MPa; or ≧800MPa and ≦2,500 MPa. In some aspects of these embodiments, the shapememory matrix material exhibits a ≧90% reduction in storage modulus asthe temperature of the shape memory matrix material is raised from(T_(g)−10)° C. to (T_(g)+10)° C., wherein the reduction in storagemodulus has a magnitude of ≧800 MPa. In some aspects of theseembodiments, the substrate is a semiconductor substrate. In some aspectsof these embodiments, the substrate is a semiconductor wafer.

In some embodiments of the present invention, the method for producing ashape memory chemical mechanical polishing pad further comprisesinterfacing the polishing layer to a base layer. In some aspects ofthese embodiments, the polishing layer is interfaced with the base layerusing an adhesive. In some aspects of these embodiments, the adhesive isselected from pressure sensitive adhesives, contact adhesives, hot meltadhesives and combinations thereof.

In some embodiments of the present invention, the method for producing ashape memory chemical mechanical polishing pad comprises: providing ashape memory matrix material transformable between an original shape anda programmed shape; preparing a polishing layer in an original stateexhibiting an original thickness, OT, comprising the shape memory matrixmaterial in the original shape; heating the polishing layer to atemperature ≧(T_(g)+10)° C.; subjecting the polishing layer to anexternal force, wherein the external force is an axial force thataxially compresses the polishing layer; setting the shape memory matrixmaterial to the programmed shape to provide the polishing layer in adensified state, wherein the polishing layer exhibits a densifiedthickness, DT; cooling the polishing layer to a temperature ≦(T_(g)−10)°C. while maintaining the axial force to set the polishing layer in thedensified state; and, removing the external force; wherein T_(g) is theglass transition temperature for the shape memory matrix material;wherein the DT is ≦80% of the OT; and, wherein the polishing layer has apolishing surface adapted for polishing a substrate selected from atleast one of a magnetic substrate, an optical substrate and asemiconductor substrate. In some aspects of these embodiments, thepolishing layer is heated to a temperature ≧(T_(g)+10)° C., but belowthe decomposition temperature for the shape memory matrix material. Insome aspects of these embodiments, the substrate is a semiconductorsubstrate. In some aspects of these embodiments, the substrate is asemiconductor wafer. In some aspects of these embodiments, the methodfurther comprises interfacing the polishing layer with a base layer. Insome aspects of these embodiments, the polishing layer is heated andcompressed in the thickness direction to facilitate programming of theshape memory matrix material and to transition the polishing layer fromthe original state to the densified state.

In some embodiments of the present invention, the method for producing ashape memory chemical mechanical polishing pad further comprises:incorporating macrotexture into the polishing layer. In some aspects ofthese embodiments, the macrotexture comprises at least one groove. Insome aspects of these embodiments, the macrotexture comprises amultiplicity of perforations. In some aspects of these embodiments, themacrotexture comprises a combination of at least one groove and amultiplicity of perforations. In some aspects of these embodiments, themacrotexture is incorporated into the polishing layer when the polishinglayer is in the densified state. In some aspects of these embodiments,the macrotexture is incorporated into the polishing layer when thepolishing layer is in the original state. In some aspects of theseembodiments, the macrotexture is incorporated into the polishing layerwhen the polishing layer is in the original state and some of themacrotexture is incorporated into the polishing layer when the polishinglayer is in the densified state.

In some embodiments of the present invention, macrotexture isincorporated into the polishing layer when the polishing layer is in thedensified state. In some aspects of these embodiments, the macrotextureis incorporated in the polishing layer using a cutting bit. In someaspects of these embodiments, it may be desirable to cool the cuttingbit or the polishing layer or both to minimize the amount of shapememory matrix material that transitions from a programmed shape to arecovered shape on account of the macrotexture incorporation process. Insome aspects of these embodiments, the process of incorporating themacrotexture into the polishing layer comprises cooling the cutting bit,cooling a region of the polishing layer in proximity with the cuttingbit or a combination thereof. In some aspects of these embodiments, thecooling can be achieved through various techniques, for example, blowingcompressed air over the cutting bit to facilitate convection, blowingchilled air over the cutting bit, spraying the cutting bit with water orblowing cooled gases on the cutting bit. In some aspects of theseembodiments, the cooling is achieved by blowing cooled, liquefied orcryogenic gas (e.g., argon, carbon dioxide, nitrogen) directly onto thecutting bit, a region of the polishing pad in proximity to the cuttingbit, or a combination thereof. In some aspects of these embodiments, thecooled, liquefied or cryogenic gas is sprayed through a specializednozzle or nozzles, wherein the gas rapidly expands, cools, and formssolid crystals or liquid to facilitate heat transfer. In some aspects ofthese embodiments, the use of such cooling techniques involve thecreation of a flow of material (e.g., gas, liquid or crystals) anddirecting the flow to encounter the cutting bit, the region of thepolishing layer in proximity with the cutting bit, or both. In someaspects of these embodiments, the flow of material directed at thepolishing pad in the region in proximity with the cutting bit has theadditional effect of aiding in the removal of chips formed in themacrotexture incorporation process. Removing these chips may bebeneficial in that it reduces the potential for the chips reattaching tothe polishing layer, for example, by melting, fusing or welding. To theextent that removing chips during the macrotexture incorporation processreduces the number of chips that reattach to the polishing layer,defects in subsequent polishing operations using the polishing layer maybe avoided. In some aspects of these embodiments, the entire polishinglayer is cryogenically cooled. In some aspects of these embodiments, theentire polishing layer and the machining fixture used to power thecutting bit is cryogenically cooled.

In some embodiments of the present invention, the external force appliedto the polishing layer to set the shape memory matrix material in theprogrammed shape is a nominal axial force that imposes a nominalpressure on the polishing layer of ≧150 psi. In some aspects of theseembodiments, the nominal pressure imposed on the polishing layer is ≧300psi. In some aspects of these embodiments, the nominal pressure imposedon the polishing layer is 150 to 10,000 psi. In some aspects of theseembodiments, the nominal pressure imposed on the polishing layer is 300to 5,000 psi. In some aspects of these embodiments, the nominal pressureimposed on the polishing layer is 300 to 2,500 psi.

In some embodiments of the present invention, the method for producing ashape memory chemical mechanical polishing pad, comprises: providing ashape memory matrix material transformable between an original shape anda programmed shape; providing a plurality of microelements; dispersingthe plurality of microelements in the shape memory matrix material;preparing a polishing layer in an original state exhibiting an originalthickness, OT, comprising the shape memory matrix material in theoriginal shape; heating the polishing layer to a temperature above theglass transition temperature, T_(g), for the shape memory matrixmaterial; applying an axial force to axially compress the polishinglayer to a densified thickness, DT, while maintaining the temperature ofthe polishing layer above the T_(g) of the shape memory matrix material;setting the shape memory matrix material in the programmed shape bycooling the polishing layer to a temperature below the T_(g) of theshape memory matrix material, while maintaining the axial force; and,removing the axial force; wherein the DT is ≦80% of the OT; wherein theshape memory matrix material exhibits a ≧70% reduction in storagemodulus as the temperature of the shape memory matrix material is raisedfrom (T_(g)−20)° C. to (T_(g)+20)° C.; and, wherein the polishing layerhas a polishing surface adapted for polishing a substrate, wherein thesubstrate is selected from at least one of a magnetic substrate, anoptical substrate and a semiconductor substrate. In some aspects ofthese embodiments, the shape memory matrix material exhibits a ≧75%reduction; ≧80% reduction; ≧85% reduction; or ≧90% reduction in storagemodulus as the temperature of the shape memory matrix material is raisedfrom (T_(g)−20)° C. to (T_(g)+20)° C.; (T_(g)−10)° C. to (T_(g)+10)° C.;or (T_(g)−5)° C. to (T_(g)+5)° C. In some aspects of these embodiments,the reduction in storage modulus has a magnitude of ≧800 MPa; ≧900 MPa;≧1,000 MPa; ≧800 MPa and ≦10,000 MPa; ≧800 MPa and ≦5,000 MPa; or ≧800MPa and ≦2,500 MPa. In some aspects of these embodiments, the shapememory matrix material exhibits a ≧90% reduction in storage modulus asthe temperature of the shape memory matrix material is raised from(T_(g)−10)° C. to (T_(g)+10)° C., wherein the reduction in storagemodulus has a magnitude of ≧800 MPa. In some aspects of theseembodiments, the method further comprises interfacing the polishinglayer with a platen of a polishing machine. In some aspects of theseembodiments, the method further comprises interfacing the polishinglayer with a platen using at least one of a pressure sensitive adhesiveand vacuum. In some aspects of these embodiments, the method furthercomprises interfacing the polishing layer with a base layer. In someaspects of these embodiments, the method further comprises attaching thepolishing layer to a base layer using an adhesive and interfacing thebase layer with the platen of a polishing machine using a pressuresensitive adhesive and/or vacuum. In some aspects of these embodiments,the densified thickness, DT, is ≦70% of the original thickness, OT. Insome aspects of these embodiments, the densified thickness, DT, is 70 to40% of the original thickness. In some aspects of these embodiments, thesubstrate is a semiconductor substrate. In some aspects of theseembodiments, the substrate is a semiconductor wafer.

In some embodiments of the present invention, the polishing layer isprepared comprising the shape memory matrix material in the originalshape by any known means to provide the polishing layer in the originalstate exhibiting an original thickness, OT. In some aspects of theseembodiments, the polishing layer is made by a process selected fromcasting, injection molding (including reaction injection molding),extruding, web-coating, photopolymerizing, sintering, printing(including ink-jet printing and screen printing), spin-coating, weaving,skiving and combinations thereof. In some aspects of these embodiments,the polishing layer is prepared by a combination of casting and skiving.

In some embodiments of the present invention, the polishing layer isconverted from the original state having an original thickness, OT, to adensified state having an densified thickness, DT, by applying a forceto compress the polishing layer at a temperature around or above theglass transition temperature, T_(g), for the shape memory matrixmaterial; cooling the polishing layer to a temperature below the T_(g)to lock in the densified thickness, DT; and removing the force appliedto compress the polishing layer.

When the shape memory matrix material in the polishing layer in aprogrammed shape is subjected to an activating stimulus it reacts bytransitioning into a recovered shape. In some embodiments of the presentinvention, the shape memory chemical mechanical polishing pads areperiodically conditioned during use when polishing a substrate to renewthe polishing surface. In some aspects of these embodiments, theconditioning process comprises the application of an activating stimulusto at least a portion of the polishing layer. In some aspects of theseembodiments, the activating stimulus is selected from exposure to heat,light, an electric field, a magnetic field, ultrasound, water andcombinations thereof. Upon exposure to the activating stimulus, theportion of the polishing layer activated increases in thickness to arecovered thickness, RT. Ideally, the total recovered thickness, TRT ofthe polishing layer upon exposure of the entire densified thickness tothe activating stimulus (hereinafter the “maximum total recoveredthickness, MTRT”) would approximate the original thickness of thepolishing layer. In practice, however, it is not critical that themaximum total recovered thickness equal the original thickness. In someaspects of these embodiments, the maximum total recovered thickness,MTRT, is ≧80% of the original thickness, OT. In some aspects of theseembodiments, the maximum total recovered thickness, MTRT, is ≧85% of theoriginal thickness, OT. In some aspects of these embodiments, themaximum total recovered thickness, MTRT, is ≧90% of the originalthickness, OT.

In some embodiments of the present invention, the polishing layer of ashape memory chemical mechanical polishing pad is periodicallyconditioned during use by heating at least a portion of the polishinglayer proximate the polishing surface to a temperature at or above theglass transition temperature, T_(g), of the shape memory matrixmaterial. As a result of this heating, some of the shape memory matrixmaterial in the polishing layer proximate to the polishing surfacetransitions to a recovered shape modifying and reconditioning thepolishing surface. In some aspects of these embodiments, the polishingsurface is also subjected to conventional conditioning processes.Notwithstanding, the response by the at least a portion of the shapememory matrix material of the polishing layer proximate to the polishingsurface to transition to a recovered shape allows polishing of severalsubstrates with similar polishing characteristics and reduces the needto periodically dress or condition the pad using conventionalconditioning processes. This reduction in conventional conditioninghelps to extend the useful life of the shape memory chemical mechanicalpolishing pads and lowers their cost of use.

In some embodiments of the present invention, perforations through thepad, the introduction of conductive-lined grooves or the incorporationof a conductor, such as conductive fibers, conductive network, metalgrid or metal wire, can transform the shape memory chemical mechanicalpolishing pads into eCMP (“electrochemical mechanical planarization”)polishing pads.

In some embodiments of the present invention, the transition temperaturefor the shape memory matrix material is selected such that standardpolishing conditions do not result in a substantial relaxation of thepolishing layer from its densified state.

In some embodiments of the present invention, the transition temperaturefor the shape memory matrix material is selected to facilitatetransition from a programmed shape to a recovered shape of a portion ofthe shape memory matrix material in the polishing layer proximate thepolishing surface induced by the conditions present during the polishingprocess. In some aspects of these embodiments, the transition is inducedby heating the slurry. In some aspects of these embodiments, thetransition is induced by heat generated at the polishing surface fromthe rigors of the polishing process.

In some embodiments of the present invention, the method of polishing asubstrate, comprises: providing a substrate selected from at least oneof a magnetic substrate, an optical substrate and a semiconductorsubstrate; providing a shape memory chemical mechanical polishing pad,wherein the polishing pad comprises a polishing layer in a densifiedstate, wherein the polishing layer comprises a shape memory matrixmaterial transformable from an original shape and a programmed shape;wherein the polishing layer in the original state exhibits an originalthickness, OT, when the shape memory matrix material is in the originalshape; wherein the polishing layer exhibits a densified thickness, DT,in the densified state when the shape memory matrix material is in theprogrammed shape; and wherein the DT is ≦80% of the OT; wherein theshape memory matrix material exhibits a ≧70% reduction in storagemodulus as the temperature of the shape memory matrix material is raisedfrom (T_(g)−20)° C. to (T_(g)+20)° C.; and, creating dynamic contactbetween a polishing surface of the polishing layer and the substrate topolish a surface of the substrate. In some aspects of these embodiments,the method further comprises renewing the polishing surface in situ orex situ by exposing at least a portion of the polishing layer proximatethe polishing surface to an activating stimulus, wherein the activatingstimulus causes a portion of the polishing layer proximate the polishingsurface to transition to a recovered state. In some aspects of theseembodiments, the densified thickness, DT, is ≦70% of the originalthickness, OT. In some aspects of these embodiments, the densifiedthickness, DT, is between 70 and 40% of the original thickness, OT. Insome aspects of these embodiments, the method further comprisesinterfacing the shape memory chemical mechanical polishing pad with aplaten of a polishing machine. In some aspects of these embodiments, themethod further comprises interfacing the shape memory chemicalmechanical polishing pad with a platen of a polishing machine using atleast one of a pressure sensitive adhesive and vacuum. In some aspectsof these embodiments, the substrate comprises a semiconductor substrate.In some aspects of these embodiments, the substrate comprises asemiconductor wafer. In some aspects of these embodiments, the substratecomprises a series of patterned semiconductor wafers.

In some embodiments of the present invention, the method of polishing asubstrate further comprises: providing a polishing medium at aninterface between the polishing surface and the substrate.

In some embodiments of the present invention, the method of polishing asubstrate further comprises: conditioning the polishing surface of thepolishing layer. In some aspects of these embodiments, the conditioningcomprises exposing at least a portion of the polishing layer proximatethe polishing surface to an activating stimulus, wherein the portion ofthe polishing layer proximate the polishing surface exposed to theactivating stimulus transitions from the densified state to a recoveredstate. In some aspects of these embodiments, the activating stimulus isselected from exposure to heat, light, a magnetic field, an electricfield, water, and combinations thereof. In some aspects of theseembodiments, the activating stimulus is exposure to heat. In someaspects of these embodiments, the activating stimulus is exposure toheat and the conditioning of the polishing surface of the polishinglayer comprises raising the temperature of a portion of the polishinglayer proximate the polishing surface to a temperature ≧T_(g), whereinT_(g) is the glass transition temperature for the shape memory matrixmaterial. In some aspects of these embodiments, the temperature of aportion of the polishing layer proximate the polishing surface is heatedto a temperature ≧(T_(g)+10)° C. In some aspects of these embodiments,the temperature of a portion of the polishing layer proximate thepolishing surface is heated to a temperature of ≧(T_(g)+20)° C. In someaspects of these embodiments, conditioning of the polishing layercomprises heating a portion of the polishing layer ≦5% of the actualthickness of the polishing layer proximate the polishing surface to atemperature≧the glass transition temperature for the shape memory matrixmaterial, T_(g). In some aspects of these embodiments, conditioning ofthe polishing layer comprises heating ≦2% of the actual thickness of thepolishing layer proximate the polishing surface to a temperature≧theglass transition temperature for the shape memory matrix material,T_(g). In some aspects of these embodiments, conditioning of thepolishing layer comprises heating ≦1% of the actual thickness of thepolishing layer proximate the polishing surface to a temperature≧theglass transition temperature for the shape memory matrix material,T_(g). In some aspects of these embodiments, conditioning of thepolishing layer comprises heating 0.1 to 5% of the actual thickness ofthe polishing layer proximate the polishing surface to a temperature≧theglass transition temperature for the shape memory matrix material,T_(g). Application of heat to only a portion of the polishing layerproximate the polishing surface is sufficient to cause some of the shapememory matrix material in that portion of the polishing layer totransition to a recovered shape, while the shape memory matrix materialin the remainder of the polishing layer remains in the programmed shape.

In some embodiments of the present invention, conditioning of thepolishing surface of the polishing layer comprises conventionalconditioning methods. In some aspects of these embodiments, conditioningof the polishing surface comprises abrading with a conditioning disk,for example, a diamond disk.

In some embodiments of the present invention, conditioning of thepolishing surface of the polishing layer comprises a combination ofconventional conditioning methods and exposure to an activatingstimulus.

In the particular embodiments described herein in reference to theFigures, the activating stimulus is exposure to heat. Notwithstanding,given the teachings provided herein, one of ordinary skill in the artwould know how to employ other activating stimuli such as, for example,exposure to light, a magnetic field, an electric field, and/or water.

In FIG. 1 there is provided a comparative depiction of an elevation viewof a polishing layer of one embodiment of the present invention. Inparticular, FIG. 1 provides a comparison of a polishing layer in anoriginal state 10 with an original thickness, OT, to the same polishinglayer in a densified state 20 with a densified thickness, DT.

In FIG. 2 there is provided a comparative depiction of an elevation viewof a polishing layer of one embodiment of the present invention. Inparticular, FIG. 2 provides a comparison of a polishing layer in anoriginal state 30 with an original thickness, OT, to the same polishinglayer in a densified state 40 with a densified thickness, DT, to thesame polishing layer in a partially recovered state 50 with a totalrecovered thickness, TRT, and with the recovered portion proximate thepolishing surface 32 having a recovered thickness, RT. The polishinglayer depicted in FIG. 2 comprises a plurality of microelements 34dispersed within a shape memory matrix material 36.

In FIG. 3 there is provided an elevation view of a shape memory chemicalmechanical polishing pad of one embodiment of the present invention. Inparticular, the shape memory chemical mechanical polishing pad 60 inFIG. 3 comprises a polishing layer 70 with a polishing surface 72,wherein the polishing layer comprises a plurality of microelements 76uniformly dispersed throughout a shape memory matrix material 74. Theshape memory chemical mechanical polishing pad 60 in FIG. 3 furthercomprises a base layer 90 interfaced with the polishing layer 70.Specifically, the base layer 90 is adhered to the polishing layer 70 byan adhesive layer 80.

In FIG. 4 there is provided a side perspective view of a shape memorychemical mechanical polishing pad of one embodiment of the presentinvention. In particular, FIG. 4 depicts a single layer shape memorychemical mechanical polishing pad 210 in a densified state having adensified thickness, DT. The shape memory chemical mechanical polishingpad 210 has a polishing surface 214 and a central axis 212. Thepolishing surface 214 has a substantially circular cross section with aradius r from the central axis 212 to the outer periphery of thepolishing surface 215 in a plane at an angle γ to the central axis 212.

In FIG. 5 there is provided a top plan view of a shape memory chemicalmechanical polishing pad of one embodiment of the present invention. Inparticular, FIG. 5 depicts a shape memory chemical mechanical polishingpad 300 having a polishing surface 302 with a groove pattern of aplurality of curved grooves 305.

In FIG. 6 there is provided a top plan view of a shape memory chemicalmechanical polishing pad of one embodiment of the present invention. Inparticular, FIG. 6 depicts a shape memory chemical mechanical polishingpad 310 having a polishing surface 312 with a groove pattern of aplurality of concentric circular grooves 315.

In FIG. 7 there is provided a top plan view of a shape memory chemicalmechanical polishing pad of one embodiment of the present invention. Inparticular, FIG. 7 depicts a shape memory chemical mechanical polishingpad 320 having a polishing surface 322 with a groove pattern of aplurality of linear grooves 325 in an X-Y grid pattern.

In FIG. 8 there is provided a top plan view of a shape memory chemicalmechanical polishing pad of one embodiment of the present invention. Inparticular, FIG. 8 depicts a shape memory chemical mechanical polishingpad 330 having a polishing surface 332 with a combination of a pluralityof perforations 338 and a plurality of concentric circular grooves 335.

In FIG. 9 there is provided a top plan view of a shape memory chemicalmechanical polishing pad of one embodiment of the present invention. Inparticular, FIG. 9 depicts a shape memory chemical mechanical polishingpad 340 having a polishing surface 342 with a plurality of perforations348.

FIG. 10 provides a top plan view of a shape memory chemical mechanicalpolishing pad 400 of some embodiments of the present invention, whereinthe polishing pad 400 has a macrotexture comprising a groove patternthat comprises at least one groove 404. The polishing pad 400 has anouter radius R_(O) and a polishing surface 402 with at least one groove404 formed therein. Although only a single groove 404 is depicted inFIG. 10, the groove pattern can comprise two or more grooves 404. (See,e.g., FIGS. 11-13). The polishing pad radius R is measured from anorigin O at the center of the polishing surface 402. A circle C_(R)(dashed line) drawn at radius R with a circumference 2πR is also shownin FIG. 10. The outer radius of polishing pad 400 is R_(O). Groove 404extends from base radius R_(B) to outer radius R_(O), which defines theouter periphery 406 of polishing surface 402. In some aspects of theseembodiments, the groove(s) 404 extend from base radius R_(B) to outerperiphery 406 (as depicted in FIGS. 10-13). In some aspects of theseembodiments, the groove(s) 404 extend from a point between the origin Oand the base radius R_(B) to outer periphery 406. In some aspects ofthese embodiments, the groove(s) 404 extend from origin O to outerperiphery 406. FIG. 14 depicts a close-up view of a groove segment ofgroove 404 of FIG. 10, showing a small differential segment 410 ofgroove 404. At a given radius R, groove 404 has a given width W and acentral axis A that forms an angle θ (“groove angle”) with respect to aradial line L connecting the origin O to the given radius R. In someaspects of these embodiments, the shape memory chemical mechanicalpolishing pad has a macrotexture comprising a groove pattern, wherein CFremains within 25%, preferably within 10%, more preferably within 5% ofits average value as a function of the polishing pad radius R in an areaextending from an outer radius R_(O) of the polishing surface a majoritydistance to origin O. In some aspects of these embodiments, the shapememory chemical mechanical polishing pad has a macrotexture comprising agroove pattern, wherein CF remains within 25%, preferably within 10%,more preferably within 5% of its average value as a function ofpolishing pad radius R in an area extending from base radius R_(B) toouter radius R_(O).

In FIG. 15 there is provided a depiction of a polishing machineutilizing a shape memory chemical mechanical polishing pad of oneembodiment of the present invention to polish a semiconductor wafer. Inparticular, FIG. 15 depicts a polishing apparatus 100 with a shapememory chemical mechanical polishing pad 110 having a central axis 112,a polishing layer 116 with a polishing surface 118 and a base layer 114.FIG. 15 further depicts a polishing platen 120 to which the base layer114 is affixed. The polishing platen 120 has a central axis 125 thatcorresponds with the central axis 112 of the polishing pad 110. Thepolishing apparatus 100 further comprises a wafer carrier 130 having acentral axis 135. The wafer carrier 130 carries semiconductor wafer 150.The wafer carrier 130 is mounted to a translational arm 140 for movingthe wafer carrier laterally relative to the polishing pad 110. The wafercarrier 130 and the platen 120 (with polishing pad 110 attached thereto)are designed to move rotationally about their respective central axisand to facilitate dynamic contact between the polishing surface 118 andthe semiconductor wafer 150. A monitor 155 is positioned (optionallymoveably positioned) relative to the polishing surface to facilitate themeasurement of at least one polishing pad property selected from apolishing pad thickness and a groove depth. A source 160 is moveablypositioned in proximity to the polishing surface 118 to facilitate theselective exposure of the polishing layer to an activating stimulus suchthat the exposed portion of the polishing layer transitions from adensified state to a recovered state. A conditioning apparatus 165provides abrasive conditioning for the polishing surface 118. Acontroller 170 is in active communication with the monitor 155, thesource 160 and the conditioning apparatus 165; and is programmed tomaintain a consistent polishing pad thickness and/or groove depth.

In FIG. 16 there is provided a depiction of a polishing apparatusutilizing a shape memory chemical mechanical polishing pad of oneembodiment of the present invention in combination with a polishingmedium (e.g., a polishing slurry). In particular, FIG. 16 depicts anapparatus 200 comprising a single layer shape memory chemical mechanicalpolishing pad 210 with a polishing surface 214 and an outer periphery215. The polishing pad 210 is interfaced with a platen 220. Thepolishing pad 210 has a central axis 212 which corresponds with acentral axis 225 of the platen 220. The apparatus 200 further comprisesa wafer carrier 230 with a central axis 235. The wafer carrier 230 holdsa semiconductor wafer 250. The apparatus 200 further comprises apolishing medium 260 and a slurry dispenser 270 for dispensing thepolishing medium onto the polishing surface 214. During polishing of thesemiconductor wafer 250, the platen 220 and the polishing pad 210 arerotated about their respective central axis and the wafer carrier isrotated about its central axis. During polishing, the polishing pad andthe wafer are placed in dynamic contact with one another and thepolishing medium is introduced to the system such that it may passbetween the semiconductor wafer and the polishing surface of thepolishing pad. The monitor 280 is positioned (optionally moveablypositioned) relative to the polishing surface to facilitate themeasurement of at least one polishing pad property selected from apolishing pad thickness and a groove depth. The source 285 is moveablypositioned in proximity to the polishing surface 214 to facilitate theselective exposure of the polishing layer to an activating stimulus suchthat the exposed portion of the polishing layer transitions from adensified state to a recovered state. The conditioning apparatus 290provides abrasive conditioning for the polishing surface 214. Thecontroller 298 is in active communication with the monitor 280, thesource 285 and the conditioning apparatus 290; and is programmed tomaintain a consistent polishing pad thickness and/or groove depth.

Some embodiments of the present invention will now be described indetail in the following Examples.

EXAMPLE 1 Shape Memory Polishing Pad

Test samples were prepared from a commercially available filledpolyurethane polishing pad (available from Rohm and Haas ElectronicMaterials CMP Inc. as IC1000™). The test samples comprised circulardiscs with a diameter of about 12.7 mm, which were die-stamped out ofpolishing pad.

EXAMPLE 2 Shape Memory Polishing Pad Material Preparation

A shape memory polymeric matrix material was prepared by mixing 227grams of glycerol propoxylate (average Mn˜266); 279 grams ofpolytetrahydrofuran (average Mn˜650), and; 494 grams ofpolycarbodiimide-modified diphenylmethane diisocyanate (available fromThe Dow Chemical Company as Isonate® 143L); at about 50° C. andatmospheric pressure. To this mixture was then blended 18 grams ofhollow elastic polymeric microspheres (available from Akso Nobel asExpancel® 551DE) at 2000 rpm using a non-contact planetary high shearmixer to evenly distribute the microspheres in the shape memory matrixmaterial. The final mixture was then poured between two flat glasssurfaces 2.54 mm apart and the 254 mm diameter pour sheet formed waspermitted to gel for about 10 minutes.

The 2.54 mm thick pour sheet along with the glass surfaces was thenplaced in a curing oven and cured for about 16-18 hours at about 105° C.The cured sheet was then cooled for about 8 hours at room temperatureuntil the sheet temperature was about 25° C.

EXAMPLE 3 Shape Memory Polishing Pad Material Preparation

A shape memory polymeric matrix material was prepared by mixing 216grams of glycerol propoxylate (average M_(n)˜266); 315 grams ofpoly(caprolactone) diol (average M_(n)˜775), and; 469 grams ofpolycarbodiimide-modified diphenylmethane diisocyanate (available fromThe Dow Chemical Company as Isonate® 143L); at about 50° C. andatmospheric pressure. To this mixture was then blended 18 grams ofhollow elastic polymeric microspheres (available from Akzo Nobel asExpancel® 551DE) at 2000 rpm using a non-contact planetary high shearmixer to evenly distribute the microspheres in the shape memory matrixmaterial. The final mixture was then poured between two flat glasssurfaces 2.54 mm apart and the 254 mm diameter pour sheet formed waspermitted to gel for about 10 minutes. The sheet was cured as in Example2.

EXAMPLE 4 Storage Modulus vs Temperature Measurements

A storage modulus in (MPa) versus temperature in (° C.) curve wasplotted for the shape memory matrix material used in commercial IC1000™polishing pads from Rohm and Haas Electronic Materials CMP Inc. (butwithout addition of Expancel® material) using a dynamic mechanicalanalyzer (DMA, TA Instruments Q800 model). The plotted curve is providedin FIG. 17.

EXAMPLE 5 Storage Modulus vs Temperature Measurements

Storage modulus in (MPa) versus temperature in (° C.) was plotted forthe shape memory matrix materials prepared as in Examples 2 and 3 (butwithout addition of Expancel® material) using a mechanical analyzer(DMA, TA Instruments Q800 model). The plotted curves are provided inFIG. 18.

EXAMPLE 6 Preparation of Polishing Pad in Densified State

Sample shape memory chemical mechanical polishing pad samples preparedaccording to Example 1 were placed between a 2″ diameter top and bottomplatens of an Instron Tester. A heated chamber, whose inside temperaturewas controllable, enclosed the space spanning the platens and the samplepads. The sample pads were heated to 120° C. for 20 minutes and an axialforce was applied to the sample pads using the platens. This axial forceimposed a nominal pressure on the sample pads, sufficient to compressthe sample pads to about 50% of there original thickness. The nominalpressure imposed on the sample pads was around 1,000-5,000 psi. Whilemaintaining the pressure, the sample pads were cooled to roomtemperature setting the shape memory matrix material therein to aprogrammed shape and providing the sample pads in a densified state.

EXAMPLE 7 Providing Polishing Pads in Densified State

12.5 mm diameter sample pads were punched out of the sheets producedaccording to Examples 2 and 3. The sample pads were then placed betweenthe 2″ diameter top and bottom platens of an Instron Tester. A heatedchamber, whose inside temperature was controllable, enclosed the spacespanning the platens and the sample pads. The sample pads were thenheated to 90° C. for 20 minutes and an axial force was applied to thesample pads using the platens. This axial force imposed a nominalpressure on the sample pads, sufficient to compress the sample pads toabout 50% of there original thickness. The pressure imposed on thesample pads by the axial force was around 1,000-5,000 psi. Whilemaintaining this imposed pressure, the sample pads were cooled to roomtemperature, setting the shape memory material in the sample pads in aprogrammed state and providing sample pads in a densified state.

EXAMPLE 8 Recovery of Polishing Pads to Recovered State

The polishing pad samples in a densified state prepared according toExample 6 were heated in an oven at 120° C. for 10-20 minutes. Theactual thickness of each of the polishing pad samples was then measured.Each of the polishing pad samples were observed to have transitioned toa recovered state with a maximum total recovered thickness of ≧99% oftheir original thickness.

EXAMPLE 9 Recovery of Polishing Pads to Recovered State

The polishing pad samples in a densified state prepared according toExample 7 were heated in an oven at 90° C. for 10-20 minutes. The actualthickness of each of the polishing pad samples was then measured. Eachof the polishing pad samples were observed to have transitioned to arecovered state with a maximum total recovered thickness of ≧99% oftheir original thickness.

EXAMPLE 10 Preparation of Shape Memory Polishing Pad in Densified State

A 203 mm diameter shape memory polishing pad was punched out of acommercial IC1000™ polishing pad. The shape memory polishing pad wasthen placed between two 254 mm dia and 12.7 mm thick flat hardened steelplates, and placed over the bottom platen of a 150 ton Hannifin, 37″×36″down-acting, 4-post hydraulic press. The top and bottom platens wereelectrically heated for over 60 minutes until the shape memory polishingpad reached a temperature of 120° C. The shape memory polishing pad wasthen compressed to about 50% of the original thickness under an axialforce imposing a pressure on the shape memory polishing pad of 1,000 to5,000 psi. While maintaining this imposed pressure, the shape memorypolishing pad was cooled to room temperature, setting the shape memorymaterial therein to a programmed shape and providing a shape memorypolishing pad in a densified state.

EXAMPLE 11 Polishing with Shape Memory Polishing Pad Using ThermalConditioning

The following experiments were performed on a chemical mechanical desktop polisher from Center for Tribology Inc. The polisher was set with adownforce of 2.4 psi, a polishing solution flow rate of 50 cc/min, aplaten speed of 160 RPM and a carrier speed of 160 RPM. The polishingmedium used was EPL2362 slurry for copper CMP available from Rohm andHaas Electronic Materials CMP Inc. The wafers used in these experimentswere 100 mm silicon substrate wafers with 15,000 Angstroms thick layerof electroplated copper available from SilyB. The wafers were polishedto remove copper. The copper removal rates in (A/min) reported hereinwere determined using wafer weight loss measurements using asubmilligram analytical balance (AINSWORTH Model #CC-204) afterpolishing the wafer for 2 minutes under the above conditions.

Polishing tests were performed using 203 mm diameter control pad die cutfrom a commercial TC1000™ polishing pad. The control pad was used inthere original state (i.e., they were not transitioned to a densifiedstate). Note that after polishing 13 wafers, the surface of the controlpad was regenerated using diamond disk conditioning. The removal rateversus wafer # data for the polishing tests performed using the controlpad in the original state with diamond disk conditioning are providedherein in FIG. 19.

Polishing tests were then performed using commercial IC1000™ polishingpad material converted to a densified state obtained using the processdescribed in Example 10. The polishing surface of the polishing pad inthe densified state was heated by bringing the polishing surface of thepolishing pad material in a densified state into contact for about 1minute with a 254 mm dia 6.4 mm thick brass plate heated to 120° C. Overthis one minute, the heating of the brass plate was continued using anelectrically controlled hot plate (Corning #PC-220) and monitoring thetemperature of the surface of the brass plate in contact with thepolishing surface. The heating of the polishing surface of the test padcaused a portion of the polishing pad proximate the polishing surface totransition to a recovered state with the remainder of the actualthickness of the polishing layer remaining in a densified state. Thepolishing pad was then used to polish 13 wafers. The surface of thepolishing pad was then heated again using the process noted above totransition another portion of the polishing pad proximate the polishingsurface to a recovered state. The pad was then used to polish wafer 14.The removal rate versus wafer # data for the polishing tests performedusing the polishing pad in a densified state with thermal conditioningare provided herein in FIG. 20.

EXAMPLE 12 Shape Memory Matrix Material Preparation

A shape memory matrix material was prepared by mixing (at about 50° C.and atmospheric pressure): 175 grams of glycerol propoxylate (averageM_(n)˜266); 349 grams of polycaprolactone (average M_(n)˜530-b-530);and, 476 grams of polycarbodiimide-modified diphenylmethane diisocyanate(available from The Dow Chemical Company as Isonate® 143L).

EXAMPLE 13 Storage Modulus vs Temperature Measurement

Storage modulus in (MPa) versus temperature in (° C.) was plotted forthe shape memory matrix material prepared as in Example 12 using amechanical analyzer (DMA, TA Instruments Q800 model). The plotted curveis provided in FIG. 21.

1. A shape memory chemical mechanical polishing pad for polishing asubstrate selected from at least one of a magnetic substrate, an opticalsubstrate and a semiconductor substrate; comprising: a polishing layerin a densified state; wherein the polishing layer comprises a shapememory matrix material transformable between an original shape and aprogrammed shape; wherein the polishing layer exhibits an originalthickness, OT, when the shape memory matrix material is in the originalshape; wherein the polishing layer exhibits a densified thickness, DT,in the densified state when the shape memory matrix material is in theprogrammed shape; wherein the DT is ≦80% of the OT; wherein the shapememory matrix material exhibits a ≧70% reduction in storage modulus asthe temperature of the shape memory matrix material is raised from(T_(g)−20)° C. to (T_(g)+20)° C., wherein T_(g) is the glass tansitiontemperature of the shape memory matrix material measured by dynamicalmechanical analysis taking the inflection point in the storage modulusversus temperature curve as the T_(g); and, wherein the polishing layerhas a polishing surface adapted for polishing the substrate.
 2. Theshape memory chemical mechanical polishing pad of claim 1, wherein thereduction in storage modulus has a magnitude of ≧800 MPa.
 3. The shapememory chemical mechanical polishing pad of claim 1, wherein the shapememory matrix material exhibits a T_(g)≧45° C. to ≦80° C.
 4. The shapememory chemical mechanical polishing pad of claim 1, wherein the shapememory matrix material exhibits a ≧90% reduction in storage modulus asthe temperature of the shape memory matrix material is raised from(T_(g)−10)° C. to (T_(g)+10)° C.; and wherein the reduction in storagemodulus has a magnitude of ≧800 MPa.
 5. The shape memory chemicalmechanical polishing pad of claim 1, wherein the shape memory matrixmaterial comprises a reaction product of a mixture comprising glycerolpropoxylate; polycarbodiimide-modified diphenylmethane diisocyanate; andat least one of polytetrahydrofuran and polycaprolactone.
 6. The shapememory chemical mechanical polishing pad of claim 1, wherein the shapememory matrix material comprises a reaction product of a mixturecomprising a polyether-based, toluene diisocyanate terminated liquidurethane prepolymer; and a 4,4′-methylene-bis(2-chloro aniline).